1. Field of the Invention
The present invention relates to a film and a laminate using the film.
2. Description of the Related Art
A polyimide film has been employed as an electric insulation film in laminate for flexible wiring board. For example, a laminate in which a conductor layer such as metallic foil and a polyimide film are laminated directly with each other or with an adhesive therebetween (see, Japanese Patent Application Laid-Open No. 58-190093).
However, the conventional polyimide film is insufficient in heat resistant and dimensional stability.
A method for producing a laminate in which a polyimide film is directly laminated on a conductor layer, has also been known. In the method, the laminate has been obtained by applying a solution of a polyimide precursor and a solvent onto a conductor layer and removing the solvent (see, “Latest polyimide—Basics and Applications—” edited by Japanese Polyimide Study Group, page 549 (2002)).
The polyimide laminate obtained by such a method, however, is insufficient in dimensional stability, since the polyimide film therein sometimes has a curled shape.